1. Field of the Invention
The present invention relates to a driving circuit for an active matrix. More particularly, the present invention relates to a scan driving circuit to drive a pixel line of an organic light emitting display.
2. Description of the Related Art
Various flat panel displays have recently been developed as alternatives to a relatively heavy and bulky cathode ray tube (CRT) display. The flat panel display includes a liquid crystal display (LCD), a field emission display (FED), a plasma display panel (PDP), and an organic light emitting display (OLED).
Among the flat panel displays, the OLED employs an emission device emitting light by recombination of an electron and a hole for displaying an image. Such an organic light emitting display has advantages of short response time and low power consumption.
FIG. 1 illustrates a schematic of a conventional OLED.
Referring to FIG. 1, the conventional organic light emitting display may include a pixel portion 30 having a plurality of pixels 40 connected to a plurality of scan lines S1 through Sn and a plurality of data lines D1 through Dm, a scan driving circuit 10 to drive the plurality of scan lines S1 through Sn, a data driver 20 to drive the plurality of data lines D1 through Dm, and a timing controller 50 to control the scan driving circuit 10 and the data driver 20.
The scan lines S1 through Sn and the data lines D1 through Dm may be formed within the pixel portion 30, and may intersect each other, forming a matrix.
The timing controller 50 may generate a data control signal DCS and a scan control signal SCS in response to external synchronous signals. The timing controller 50 may supply the data control signal to the data driver 20 and the scan control signal SCS to the scan driving circuit 10. The timing controller 50 may also supply DATA to the data driver 20.
The scan driving circuit 10 may receive the scan control signal SCS from the timing controller 50. The scan driver 10 may generate a scan signal based on the scan control signal SCS and may supply the scan signals to the scan lines S1 through Sn in sequence.
The data driver 20 may receive the data control signal DCS from the timing controller 50. The data driver 20 may generate a data signal based on the data control signal DCS and may supply the data signals to the data lines D1 through Dn while synchronizing with the scan signals.
The pixel portion 30 may receive a first power source voltage ELVDD and a second power source voltage ELVSS and may apply them to the respective pixels 40. Each of pixels 40 may receive the first and second power source voltages ELVDD and ELVSS and may control a current flowing from the first power source voltage ELVDD to the second power source voltage ELVSS via the emission device on the basis of the data signal, thereby emitting light corresponding to the data signal.
In the OLED with the foregoing configuration, coupling capacitance may arise at the intersections between scan lines and the data lines. Therefore, the scan signals sequentially supplied from the scan driving circuit 10 to the scan lines S1 through Sn may be changed by the coupling capacitance due to the data lines intersecting the scan lines.